ES2286007T3 - PACK WITH PANELS RESPONDING TO PRESSURE. - Google Patents

Abstract

A container (1) suitable for containing liquid and having at least one controlled deflection flexible panel (3) to adapt to the pressure changes induced within the container, wherein said flexible panel (3) has longitudinal and transverse extensions defining a plane of said flexible panel (3), said longitudinal and transverse extensions being relative to a longitudinal axis of said container, said flexible panel (3) having a flex region (5) projecting at a distance from said characterized plane because said panel has a flexion initiation region (8) located longitudinally at a distance from said flexion region (5), said flexion initiation region (8) having a smaller amount of arc that projects at a distance from said plane that said bending region (5) said regions merging longitudinally with each other within the panel, the amount of arc progressively increasing from said starting region ation up to said flexion region, so that said initiation region (8) can flex inwards with respect to said plane and in which, in response to pressure changes, the amount of arc changes changes and causes said region of flexion (5) is progressively reduced in said amount of arc in response to the increase in pressure changes produced within the package.

Description

Package with panels that respond to the Pressure.

Technical field

The present invention relates to a container pressure adjustable, and more specifically, to the field of packaging of polyester capable of being filled with hot liquid, and at a improved sidewall construction for such containers.

Background of the invention

The "Hot Load" applications impose considerable and complex mechanical stresses on the container structure due to thermal stress, pressure hydraulic after filling and immediately after application of the cap, and to the vacuum pressure when the fluid is cools

The thermal stress is applied to the walls of the container after the introduction of hot fluid. Hot fluid may cause the walls of the container to soften and to then they contract unevenly, causing container distortion Polyester must, therefore, be heat treated to induce molecular changes by giving as a result a container that shows thermal stability.

Pressure and effort are applied to the side walls of a heat resistant container during filling process, and for a later period of time considerable. When the container is filled with hot liquid and hermetically sealed, there is an initial hydraulic pressure and it exerts an increased internal pressure on the containers. When the liquid, and the upper air space located under the cap, subsequently cooled, the thermal contraction translates into a partial creation of container vacuum. The void created by this cooling tends to mechanically deform the walls of the container.

Generally speaking, packages that incorporate a plurality of longitudinal flat surfaces adapt the vacuum force more easily. Agrawal et al ., US Patent No. 4, 497,855 discloses a package with a plurality of crushed panels, separated by terminal areas, which allows uniform inward deformation under the force of vacuum. The effects of the vacuum are controlled without negatively affecting the appearance of the container. The panels are delineated inwards to give way to the vacuum and thereby prevent excessive force from being applied to the structure of the container, which would otherwise deform the structures of the upright areas or terminal areas. The amount of "bending" available on each panel is limited, however, and as the limit approaches there is an increased amount of force that is transferred to the side walls.

To minimize the effect of force transferred to the side walls, much of the technique Previous has focused on the incorporation of rigid regions in the package, including the panels, to prevent the structure yields to the force of the vacuum.

Document EP0505054 on which the preamble of Claim 1, proposes a partial solution to this problem using a solidarity hinge structure continues surrounding the panel.

The provision of horizontal or vertical annular sections or "ribs" along the package has been a common practice in the construction of containers, and is not restricted solely to hot-load containers. These annular sections will reinforce the part on which they are deployed. US Patent No. 4,372,455 to Cochran discloses an annular reinforcement rib in a longitudinal direction, located in the areas between flat surfaces that are subjected to inward hydrostatic deformation forces under the force of vacuum. US Patent No. 4,805,788 to Akiho Ota et al discloses ribs that extend longitudinally along the panels to contribute to the rigidity of the container. Akiho Ota also discloses the reinforcing effect of providing a greater step on the sides of the terminal areas. This provides greater dimension and resistance to the rib areas between the panels. US Patent No. 5,178,290 of Akiho Ota et al ., Discloses indentations to reinforce the very areas of the panels.

US Patent No. 5,238,129 of Akiho Ota et al ., Also discloses an annular reinforcement rib, this time in horizontally directed strips above and below, and outside, of the hot load panel section of the bottle.

In addition to the need to reinforce a container both against thermal stress and vacuum, there is a need to enable an initial hydraulic pressure and an internal pressure increased to be applied on a container when it is introduced hot liquid followed by the application of the cap. This causes application of an effort on the side wall of the container. There's a forced outward shifting of hot panels, which It results in a bulge of the container.

Thus, Hayashi et al ., US Patent No. 4,877,141, discloses a panel configuration that adopts an initial, and natural, outward bending caused by internal hydraulic pressure and temperature followed by an inward pressure caused by the formation of vacuum during the cooling It should be noted that the panel is kept in a relatively flat profile, but with a slightly displaced central portion to increase the resistance of the panel but without preventing its radial movement in and out. Being, however, the generically flat panel, the amount of displacement is limited in both directions. Necessarily, no panel ribs are included to obtain extra resilience, as this would prohibit the return movement out and into the panel as a whole.

Krishnakumar et al ., US Patent 5,908,128 discloses another flexible panel intended to react to hydraulic pressure and temperature forces that occur after filling. A relatively standard "hot load" style container geometry for a "pasteurizable" package is disclosed. It is claimed that the pausterization process does not require that the container be thermofixed before filling, because the liquid is introduced cold and is heated after applying the cap. Concave panels are used to compensate for pressure differences. To provide flexibility in radial outward displacement followed by radial inward displacement, however, the panels are maintained in a shallow inward curvature to adapt to the changing internal temperatures and pressure of the pasteurization process. The increase in temperature after plugging, which is maintained for some time, softens the plastic material and, therefore, allows the inwardly curved panels to flex more easily under the induced force. It is reported that too much curvature would prevent this. However, permanent deformation of the panels when they are forced to adopt an opposite curvature is prevented by shallow conformation of the curvature, and also by softening the heat-subjected material. The amount of force transmitted on the walls of the container, therefore, is again determined by the amount of bending available in the panels, as it is in a standard hot load bottle. The amount of bending is limited, however, due to the need to maintain a shallow curvature on the radial profile of the panels. Accordingly, the bottle is reinforced in many standard ways.

Krishnakumar et al ., US Patent 5,303,834, also discloses other "flexible" panels that can move from a convex position to a concave position, providing an "oppressive" container. The single vacuum pressure cannot reverse the panels, but they can be manually forced to produce the inversion. The panels automatically recover their original form after the pressure is released, as a considerable amount of force is needed to keep them in an inverted position, and this must be maintained manually. The permanent deformation of the panel, caused by the initial convex presentation, is avoided by using multiple longitudinal flexion points.

Krishnakumar et al ., US Patent 5,971,184 discloses other "flexible" panels that claim their removable nature from a first convex position to a second concave position by providing a bottle with a grip neck comprising two large flattened sides. Each panel incorporates an indented central portion "invertible". Containers such as this, in which there are two large and flat opposite sides, differ in terms of the stability of the vacuum pressure of the hot-load containers that are intended to maintain a generically cylindrical shape subjected to vacuum traction. The side walls of the widened panels are subjected to increased suction and are pulled into the concavity to a greater extent than if each wall had a smaller size, as in a "standard" configuration consisting of six panels in a container substantially cylindrical. Thus, said container structure increases the amount of force supplied to each of the two panels, thereby increasing the amount of bending force available.

However, the convex portion of the panels must remain relatively flat, however, or the force of the vacuum cannot pull the panels adopting the required concavity. The need to maintain a shallow curvature to enable flexion to take place was previously described by Krishnakumar et al in US Patents 5,303,834 and 5,908,128. This in turn limits the amount of vacuum force that is released before deformation is applied to the walls of the container. Likewise, in general it is considered impossible that a shape that is convex in both the longitudinal and horizontal planes is reversed satisfactorily, unless it has a very superficial convexity. Moreover, the panels cannot then return to their original convex position after the release of the vacuum pressure when the cap is removed if there is any significant amount of convexity in the panels. In the best case, a panel can be subjected to "forced pressure" and will be locked adopting a new inverted position. The panel is then unable to reverse its direction, since there is no influence of heat from the liquid to soften the material and there is insufficient force available from the ambient pressure. On the other hand, there is no longer the contribution derived from the memory force that was available with the plastic before being subjected to pressure until it adopts a concave position. Krishnakumar et al ., In US Patent 5,908,128 previously disclosed the incorporation of longitudinal ribs to prevent such permanent deformation from occurring when the arches of the panels were flexed from a convex position to a concave position. This same observation related to permanent deformation was also disclosed in US Patent 5,303,234 to Krishnakumar et al . Hayashi et al ., In US Patent 4,877,141 also disclosed the need to keep the panels relatively flat if they had to flex against their natural curvature.

The main failure of the technical packaging The former considers the applicant that the deformation is not recoverable from the structural geometry of the container, due to its weakness, when there is a vacuum pressure inside the container, and especially when said container has been subjected to a decrease in material weight for commercial reasons.

The present invention, on the contrary, enables increased flexion of the side walls of the vacuum panels, so that the pressure on the containers can Be more easily adapted. Various can still be used types and locations of reinforcement ribs, according to previously described, to compensate for any remaining effort which must inevitably appear as a result of flexion of the container walls when subjected to the new state of "pressure adjusted" by environmental forces.

Object of the invention

Thus, it constitutes an object of the invention solve or at least alleviate these problems from current packaging, or at least provide the public with an alternative Useful.

Additional objects of the present invention they may be evident from the description that follows.

Summary of the invention

In accordance with the present invention, provides a package according to claim 1.

In a preferred manner, the regions are project in an outward direction with respect to the plane.

In another preferred form, the regions are project in an inward direction with respect to the plane.

In a preferred form, the flexible panel can be substantially arched.

In an alternative way, the flexible panel can include two flexible panel portions that are in an apex.

Preferably, the flexible panel may be located between relatively rigid terminal areas.

In a preferred form, the or each portion of initiation can be located substantially at one end of said flexible panel.

In an alternative preferred form, the portion initiation can be located substantially towards a center of said flexible panel.

Preferably, the or each initiation portion may include a substantially flattened portion.

Preferably, the flattened portion may be located at a distal end of said initiation portion with compared to the rest of the flexible panel.

In a preferred way the or each portion of initiation can project in an opposite direction with respect to to the rest of the flexible panel.

Preferably, a border between said initiation portion and the rest of said flexible panel may be  substantially arched in the circumferential direction of panel.

In a preferred manner, the extent of the Flexible panel projection can be progressively increased to distance from said initiation portion.

In an alternative way, the extension of Flexible panel projection can remain substantially distance constant of said initiation portion.

Preferably, the package may include a connection portion between said flexible panel and said areas terminals, the connection portion is adapted to place said flexible panel and said terminal areas in a circle different from the center of the container.

Preferably, the connection portion may be substantially "U" shaped in which the side of the connection portion to the flexible panel is adapted to flex substantially tense the "U" shape when the flexible panel is in a first position and return to the shape of "U" when the flexible panel is reversed from the first position.

Preferably, the extent of the projection of the initiation portion can be adapted to enable that of flexion of the initiation portion after cooling of a predetermined liquid introduced into the container at a temperature default

Preferably, the flexible panel can be adapted to be reversed in use after flexing the portion of initiation.

Additional preferred features are set forth in the dependent claims.

Additional aspects of the invention will result. evident from the subsequent description provided by way of example only and in which reference is made to accompanying drawings

Brief description of the drawings

Figure 1: shows an elevation view of a container according to a possible embodiment of the present invention

Figure 2a: shows a panel section in elevation of the container shown in figure 1.

Figure 2b: shows a side view of the panel section shown in Figure 2a.

Figure 3: shows a side view of the panel section shown in Figure 2b inverted.

Figures 4a to c: show representations schematics of the cross section of the container of Figure 1 a along the A-C lines, respectively, when The panel sections are not inverted.

Figures 5a to c: show representations schematics of the cross section of the container of Figure 1 a along the A-C lines, respectively, when The panel sections are inverted.

Figures 6a to c: show front views and sides of an alternative embodiment of a section of panel.

Figure 7a: shows a front elevation view of a further alternative embodiment of a section of panel.

Figures 7b, c: Show side views of the panel section of Figure 7a in the non-inverted positions e inverted, respectively.

Figure 8a: shows a front elevation view of a further alternative embodiment of a section of panel.

Figures 8b to d: show side views of the panel section of Figure 8a in a non-inverted position, partially inverted, and fully inverted, respectively.

Figures 9a to c and Figures d to f: show schematic representations of the cross section through the lines corresponding to A-C respectively, of the container of Figure 1 with an additional panel section alternative, in positions, respectively, not inverted and inverted

Detailed description of the drawings

With reference to Fig. 1, according to a Preferred form of the present invention, a package is indicated in general terms with reference numeral 1 with a portion of main side wall 1 of cylindrical shape generically rounded.

Container 1 is an adjustable pressure container, in particular a "hot load" container that is adapted to be filled with a liquid at a temperature above the room temperature. The container 1 can be shaped in a mold by blowing and can be manufactured with polyester or other material plastic, such as a polyethylene terephthalate (PET) heat set. The bottom of the side wall portion 2 includes a plurality of elongated 3 oriented vacuum panels vertically they are arranged around the circumference of the container, separated from each other by elongated terminal areas 4 vertically smooth. Each panel can have a form generically rectangular and is adapted to flex inward after the filling the container with a hot filling liquid, the capping of the container, and the subsequent cooling of the liquid. During the process the vacuum panels 3 operate to compensate for the vacuum of the hot load

With reference now to Figure 2a, it shows a vacuum panel 3 of the container 1. The vacuum panel 3 includes at least one connection portion 7 that connects a portion protrusion 5, with the terminal areas 4. The protruding portion 5 includes an initiation portion 8, which controls a union of the projecting portion 5 and the connection portion 7. Preferably, the connection portion 7 is capable of flexing inward under the force of pressure with relative ease and the pressure portion 8 causes the protruding portion 5 to fold first by inverting and then flexing more inward This causes a much greater volume evacuation by vacuum panels 3 than existing flexible panels. The vacuum pressure is then reduced to a greater degree that in the existing containers causing a lower effort to the side walls of the container.

Preferably, the connection portion 7 enables the radius from the center of the container 1 at the edge of flexible panel 3 (inside connection portion 7) be fixed regardless of the edge radius of the terminal areas 4 (outer border that borders connection portion 7). So, the connection portion 7 allows the terminal area 4 to be complete independently on one side, and that flexible panel 3 is complete, and in optimal situation to produce the flexion on the other side. The connection portion 7 bridges any difference circumferential radial on the two structures.

Border 8A between initiation portion 8 and the rest of the projecting portion 5 is shown in a shape substantially arched in the zinc-directional panel direction 3.

The amount of arc or projection of the portion of initiation 8 with respect to a plane defined by the axis central longitudinal of the container is significantly smaller than the arc or projection of the projection portion 5, making it more susceptible to vacuum pressure. The initiation portion 8 also includes an initiation end 9 that is predominantly flattened, and is the most susceptible to the pressure of empty. Thus, when the container 1 is subjected to a vacuum pressure, the vacuum panel 3 can flex in the extreme portion of initiation 9 followed by flexion and then inversion of the entire initiation portion 8 and the subsequent continuation of the inversion of the projecting portion 5. In one embodiment alternatively, the initiation end 9 may be concave. Without However, in this embodiment, the extent of the projection of the concave portion with respect to the plane defined by the central longitudinal axis of the container is still smaller than the magnitude of the projection of the rest of the outgoing portion 5.

It should be appreciated that the portion investment outgoing 5 can progress steadily in response to the gradual contraction of the volume of the contents of container 1 during the cooling This contrasts with a panel that "oscillates" Between two states The gradual flexion of the protruding portion 5 to and from the investment in response to a pressure difference relatively small compared to the panels that "oscillate" means that less force is transmitted to container walls This allows less material to be used that the necessarily used in the construction of the container, Making the production cheaper. Consequently, fewer failures under load they can take place with the same amount of material from container.

Also, the pressure difference reduced necessary to reverse the projecting portion 5 enables the inclusion of a greater number of panels 3 in a single container 1. The panel 3 also does not need to be large, as provides a low vacuum force to initiate flexion of the panel. Thus, panels 3 need not be large, nor of reduced number in a container structure, providing a greater flexibility in packaging design.

Figure 2b shows a cross section to along the D-D line of Figure 2a. Panel 3 shows a protruding portion 5 in its non-inverted position, indicating the dotted line the border of the outgoing portion 5 with the connection portion 7. In the preferred form of the invention, the projecting portion 5 is substantially arched in a radial or transverse direction outward, as indicated by the direction of the arrow 6. The connection portion 7 It is substantially "U" shaped, determining the heights relative of the sides of the "U" the relative radius in which the terminal areas 4 and the projecting portion 5 are located. The initiation end 9 is the most susceptible to vacuum pressure because it is projected to the minimum extent, that is, with the smaller arch of the protruding portion 5.

Figure 3 shows a panel 3 with the portion outgoing 5 inverted due to vacuum pressure applied. He initiation end 9 and initiation portion 8 are folded and invest in the first place, effectively pulling the area adjacent outgoing portion 5 inward. This continues at length of the outgoing portion 5 until the outgoing portion is completely inverted as shown in reference 5b. The dotted line in Figure 3 shows the edge of the portion projection 5 and the shaded line 5a shows the position of the outgoing portion when not inverted.

It is noteworthy that, when the vacuum pressure It is released after removal of the cap from the container, panel 3 is able to recover from its fixed vacuum position and return to Its original configuration. This can be complemented by a uniform graduation of the arc curvature from one end of the protruding portion 5 to the other, progressively increasing the arc of remote curvature of the initiation portion 8. When the pressure is released, the initiation portion 8 causes the panel bowed in 3 satisfactorily reverse your address in transverse direction, beginning with the inversion of the portion of initiation 8 and following the raised outgoing portion 5 without it is subjected to a non-recoverable deformation. Panel vacuum 3 can repeatedly be reversed without deformation permanent significant.

Figures 4a to c show representations in cross section of the container 1 shown in Figure 1 along of lines AA, BB, and CC, respectively, with the portions projections 5 in the non-inverted position. In this form of preferred embodiment, the projecting portion 5 is projected progressively farther out the portion of initiation 8.

Figures 5a to c show representations in cross section of container 1 along lines AA, BB, and CC, respectively, with the protruding portion 5 in the position completely inverted, 5b, due to the vacuum pressure applied. The area of the protruding portion 5 around the line A-A curves to a relatively large point in comparison with the areas closest to the initiation portion 8. Dotted lines 5a of Figures 5a to c indicate the position of the protruding portions 5 without vacuum pressure.

Figure 6a shows an embodiment alternative of a vacuum panel 30 with an initiation portion 80 and a flattened region 90. The connection portion 70 of the panel void 30 is a planar member surrounding the projection portion 50. Figure 5b shows the vacuum panel 30 without a pressure of vacuum applied. The projecting portion 50 has an arc curvature remote constant of the initiation region 80 in the direction of arrow 6. Figure 6c shows the vacuum panel 30 with its protruding portion 50 in a completely inverted position due to the application of vacuum pressure.

Figure 7a shows an elevation view of a additional embodiment of a vacuum panel 300. The panel Vacuum 300 includes two adjacent portions 500 located vertically adjacent to each other. The initiation portion 800 is extends in two directions from a central initiation end 900. In this embodiment, the center of the vacuum panel 300 is susceptible to deflection to a maximum degree under a pressure vacuum and therefore flexes first. Figures 7b and 7c show the vacuum panel 300 without pressure being applied of vacuum and in the completely inverted position, respectively.

Dotted line 800a illustrates the border arched between the 800 initiation portions and the rest of the 500 outgoing portions.

Figure 8a shows an elevation view of a additional alternative embodiment of a vacuum panel generically designated with the arrow 300 1. Vacuum panel 300 1 includes two projection portions 500 1 and 500 11 located vertically adjacent to each other including respective initiation portions 800 1, including, a central flattened region 9001. However, unlike the  vacuum panel 300, the nominal position of one of the portions projections 500 11 is concave and not convex (see Figure 8b). After the application of hydraulic pressure, the protruding portion concave 500 11 is inverted in the direction shown with the arrow 6a (see Figure 8c), reducing the pressure on the terminal areas (4) between adjacent panels 300 1. One time that the fluid cools, the vacuum pressure causes both the protruding portions 500 1 as 500 11 are reversed in the arrow direction 6B. (See Figure 8d).

It should be appreciated that the profile and / or configuration of the vacuum panels can be varied. For example, how do you shown in Figure 9, the container (1) may have panels of empty with a 5 1 encouraging portions that includes two planar portions 10 that are at an apex 11 to form an angled panel, as opposed to an arched panel. The figures 9a to c show cross sections along the lines AA, BB, and CC, respectively, of container 1 of Figure 1 but with said protruding portions 5 1. Figures 9d to f show the inverted positions of the protruding portions 5 1 of the Figures 9a to c, respectively, with the continuous lines 5 1 b showing the inverted position and dotted lines 5 1 at positions before the investment. Additionally or alternatively, panels 3 of any of the embodiments may be arranged transversely with respect to the longitudinal axis of the container  and not vertically, as shown in Figure 1, by example.

This is how a pressure container is provided adjustable that includes flexible panels that allow a great  change in volume in the contents of the container and, for consequently, the application of a reduced pressure on the side walls. Consequently, a content of the reduced material to support the integrity of the container and the packaging can thus be cheaper to manufacture.

When the previous description has been done reference to specific components or all of the invention having known equivalents, in this case, said equivalents are incorporated herein as if individually will be incorporated.

Although the present invention has been described in example mode and with reference to possible embodiments of the same, it should be understood that modifications or improvements therein without departing from the scope of the invention such as It is defined in the attached claims.

Claims (24)

1. A container (1) suitable for containing liquid and having at least one controlled deflection flexible panel (3) to adapt to the pressure changes induced within the container, wherein said flexible panel (3) has longitudinal extensions and transverse defining a plane of said flexible panel (3), said longitudinal and transverse extensions being relative to a longitudinal axis of said container, said flexible panel (3) having a flex region (5) projecting at a distance from said plane characterized in that said panel has a bending initiation region (8) located longitudinally at a distance from said bending region (5), said bending initiation region (8) having a smaller amount of arc projecting at a distance from said plane that said flexion region (5) fusing said regions longitudinally with each other within the panel, the amount of arc progressively increasing from said region of in iciation to said flexion region, so that said initiation region (8) can flex inwardly with respect to said plane and in which, in response to pressure changes, the amount of arc changes changes and causes said flexion region (5) is progressively reduced in said amount of arc in response to the increase in pressure changes produced within the container. 2. A package according to claim 1 characterized in that said flexion region (5) projects outwardly in a transverse direction with respect to said longitudinal axis. 3. A package according to claims 1 or 2 characterized in that said flexion of said flexion region (5) causes a decrease in curvature out of said projection out of said flexion region (5). 4. A package according to claims 1, 2 or 3 characterized in that said initiation region (8) has an outward curvature that merges smoothly with said flexion region (5). A package according to claims 1, 2 or 3 characterized in that said initiation region (8) has an inward curvature that merges smoothly with said flexion region. A package according to claim 1 characterized in that an extension of said arc with respect to said plane varies along an axis of said container (1). A package according to claim 1 characterized in that said initiation region (8) varies in an extension that radiates transversely along said longitudinal axis of said container (1). A package according to claim 7 characterized in that said flexion region (5) varies in an extension that radiates transversely along said longitudinal axis of said container (1). 9. A container according to claim 7 characterized in that the initiation region (8) is inverted to reverse its curvature in response to a change in the vacuum pressure produced within said container (1). 10. A container according to claim 9 characterized in that said flexion region (5) is inverted to reverse its curvature in response to a change in vacuum pressure within said container (1). 11. A package according to claim 1 wherein said package (1) is adapted to contain liquid at an elevated temperature above room temperature, said flexible panel (3) being adapted to be inverted after a change in pressure internal during a change in the temperature of said liquid, characterized in that said initiation region (8) is adapted to invert with respect to the direction of its projection thereby causing said flexion region (5) to be reversed with respect to the direction of its projection. 12. A package according to claim 11 characterized in that said flexible panel (3) is adapted to flex inwards after a decrease in internal pressure during cooling of said liquid. 13. A package according to claims 11 or 12 characterized in that said amount of arc is produced in an outward direction with respect to said plane. 14. A package according to claim 13 characterized in that said flexible panel (3) is adapted to flex outwardly in use after raising an internal pressure during a heating of said liquid. 15. A package according to claim 11 characterized in that said amount of arc is produced in an inward direction with respect to said plane. 16. A package according to claim 11 characterized in that said package (1) includes a plurality of flexible panels (3) separated along said longitudinal axis. 17. A package according to claim 11 characterized in that the or each panel (3) includes one or more of said substantially central region (s) (8), extending a pair of said flexible regions (5) ) at a distance from said initiation region (s) (8) towards the opposite longitudinal ends of said flexible panel (3). 18. A package according to claim 1 characterized in that said initiation region (8) is located closer to the center of the flexible panel (3) and said flexible panel (3) having a first and second flexion regions (5) which extend longitudinally at a distance from said initiation region (8), said first flexion region (5) extending towards a first end of said flexible panel (3) and said second flexion region (5) extending towards said opposite end of said flexible panel (3). 19. A package according to claim 18 adapted to contain liquid at an elevated temperature above the ambient temperature characterized in that said initiation region (8) and / or said flexion region (5) have a curvature that varies in a extension that radiates transversely along an axis of said container (1). 20. A package according to claim 19 characterized by having a pair of substantially rigid regions between which said initiation region (8) and said flexion region (5) extend, a flattened region (900 ') extending between said rigid regions to provide an extreme portion of said initiation region
(8). 21. A package according to claim 1 characterized in that the initiation region (8) and / or the flexion region (5) provide two panel portions (3) that converge on an apex (11). 22. A package according to claim 1 characterized in that the flex region (5) is located towards a first longitudinal end of said flexible panel (3) and said initiation region (8) is located towards an opposite longitudinal end of said flexible panel (3). 23. A package according to claim 1 characterized in that said initiation region (8) is projected at a distance from said plane to an extent smaller than said flexion region (5). 24. A package according to claim 1 characterized in that said initiation region (8) is located closer towards a first longitudinal end of said flexible panel (3) than said flexion region (5).